Use the 2D drawing tools to create or modify the graphics that will be used for the new block, or drag a file into the active document. To include a label in the block definition, create the label first with the Block Label command.
Tip:
Alternatively, you can (1) define the block graphics first, and then (2) use the Open command to open the master block for editing, and (3) create and add the label to the block.
Choose Sketching tab→Blocks group→Block 
command.
(Assign block graphics properties) On the Block command bar, click the Block Options button, and then enter block attributes and values in the Block Options dialog box.
(Select Block Contents) In the document, do all of the following:
Select the individual elements to include in the block, or use a fence to select a group of elements or objects.
The elements highlight to show they are selected. To deselect an element from a group, press Shift when you click.
Click Accept (green check mark).
Click a point on the block graphics or in free space to define an origin point for the block.
(Specify block name) Assign a different name to the block by typing it in the Name box and pressing Tab.
Tip:
You also can use the default block name is displayed on the command bar.
(Optional) To lock the graphics so that they cannot be replaced, clear the Place Occurrence button on the command bar.
Tip:
Set by default, this option enables you to replace the graphics in the block with different or updated graphics.
(Optional) To disable text scaling, clear the Scale Block Text button on the command bar.
Tip:
Set by default, this option automatically scales text inside the block when the block graphics are resized.
Do one of the following:
Click Accept to create the block using the definition criteria.
Click Discard (red x) to discard the input and start over.
Click the Select tool or press Esc to exit block creation mode.
Tip:
You may find it helpful to work on the 2D Model sheet if you want to drag and drop a file into the document. Select the View tab→Sheet Views group→2D Model command, and then click the 2D Model sheet tab to display it.
You can view and manage the blocks you create using the Block Library File List and Block Selection Pane in the Block Library. Click the Show Blocks button 
to display the blocks.
You can add blocks to groups, and you can select groups to be included in blocks.
A nested group can consist of a combination of individual elements and other blocks. To select the graphics in a block occurrence, you may need to first Unblock the block occurrence.